Relationship between nitrogen mustard drug resistance in B-cell chronic lymphocytic leukemia (B-CLL) and protein expression of Bcl-2, Bax, Bcl-X and p53.
Several genes have been implicated in the regulation of apoptosis including bcl-2, bax, bcl-X and p53. These genes may be important in the development of nitrogen mustard (NM) drug resistance in B-cell chronic lymphocytic leukemia (B-CLL). Using Western blot analysis, we examined the levels of Bcl-2, Bax, Bcl-X and p53 protein expression and determined whether the levels of these proteins correlated with in vitro drug resistance in CLL patients' lymphocyte samples. Our investigations suggest that in CLL, NM drug resistance develops without any detectable alteration of Bcl-2, Bax or Bcl-X. In addition, we determined the presence of p53 mutations in 14 samples in order to assess if there is an association between in vitro drug resistance and the presence of p53 mutations. Using single-stranded conformational polymorphism (SSCP) and sequencing analysis, we observed a p53 mutation in two out of seven resistant samples. The mutation occurring in both cases was a G:C --> A:T transition at codon 273 (exon 8). One of these cases was de novo resistant to the nitrogen mustards. Only one of six samples with acquired resistance to the nitrogen mustards had a p53 mutation suggesting that p53 mutations are not a prominent feature of acquired NM resistance in CLL.
Christodoulopoulos
G
G
Lady Davis Institute for Medical Research, Sir Mortimer B. Davis Jewish General Hospital, Montreal, Quebec, Canada.
Fotouhi
N
N
Krajewski
S
S
Reed
J C
JC
Alaoui-Jamali
M
M
Panasci
L
L
D000368:Aged; D000369:Aged, 80 and over; D018906:Antineoplastic Agents, Alkylating; D017209:Apoptosis; D015153:Blotting, Western; D019008:Drug Resistance, Neoplasm; D004354:Drug Screening Assays, Antitumor; D005260:Female; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008466:Mechlorethamine / Q000627:therapeutic use*; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism*; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein
D018906:Antineoplastic Agents, Alkylating; C494826:BAX protein, human; C494811:BCL2L1 protein, human; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D051020:bcl-X Protein; D008466:Mechlorethamine